At my request we were heading into the Panamint Valley as I had never been there before. As we got to the south end in the valley Mark suggested some slow flight demonstrations. I had Visions of flameouts and rolling inverted with flat spins to the deck as he slowed the plane to about 80 mph. Hanging off the thrust, nose high in the sky, laying on our backs, the power had been increased and we oscillated slightly in both pitch & roll and did 180 degree heading changes . This kind of speed and attitude is like flying a hang glider at about 8 mph. Without the lift from the thrust (if you know what I mean) it would be impossible. The sensation of tumbling from such attitudes and speeds because of my references to how a hang glider would behave made this quite spooky.
For a moment I felt as though the lunch I had was a bad idea and unzipped my right shin pocket where I had stowed my airsick bag just in case the feeling got worse. At first I suspected the slow flight and the uneasy feelings it created as being the cause of the nausea but after the flight I had time to reflect on the whole chain of events and believe that it was the multiple aileron rolls we did a few minutes earlier as the cause and it just took about 5 minutes for my body to react to them. My advice to you is... if you ever get a hop in one of these things, leave the rolls to the end so as not to interfere with the rest of the flight.